Grinding machines



A. SUMNER ETAL GRINDING MACHINES Filed Sept. 19, 1966 I NVEN TORS ALBERT SUMNER GEOFFREY I. ABELL ATTORNEY Jan. 6, 1970 United States Patent 3,487,587 GRINDING MACHINES Albert Sumner, Poynton Park, Cheshire, and Geoffrey I.

Abel], Haughton Green Denton, England, assignors to F. E. Rowland & Co. Ltd., Stockport, Cheshire, England, a British company Filed Sept. 19, 1966, Ser. No. 580,518 Int. Cl. B24b 47/10 US. Cl. 51134.5 8 Claims ABSTRACT OF THE DISCLOSURE A grinding machine having a casing for partially enclosing a grinding wheel comprising a pivotally mounted nose piece adjustable to maintain an edge thereof closely spaced from the periphery of a grinding wheel. A mechanical connection between the nose piece and a. control device for the grinding wheel motor is provided for adjusting the speed of the latter in accordance with the position of the nose piece in order to maintain constant peripheral speed of the grinding wheel during a grinding operation.

This invention relates to grinding machines, and more particularly, to means for controlling the speed of rotation of a grinding wheel.

When a grinding machine is in use, the diameter of the grinding wheel steadily decreases due to wear and, unless the speed of rotation of the wheel is increased appropriately, the metal removal rate and the efliciency of the grinding machine is reduced.

The general purpose of the present invention is to maintain the peripheral speed of the grinding wheel substantially constant regardless of the wear of said wheel.

Accordingly, it is an object of the present invention to provide a new and improved grinding machine.

It is another object of the present invention to provide a new and improved grinding machine having control means for adjusting the speed of rotation of a grinding wheel.

It is a further object of the present invention to provide a new and improved grinding machine having control means for adjusting the speed of rotation of a grinding wheel to compensate for wear of the wheel.

It is still another object of the present invention to provide a new and improved grinding machine having control means for adjusting the speed of rotation of a grinding wheel to compensate for wear of the wheel and maintain the peripheral speed of such wheel substantially constant during grinding.

These objects may be accomplished according to one embodiment of the invention by providing a casing for partially enclosing a grinding wheel comprising side walls and a portion extending about the periphery of the wheel and terminating in a nose piece. The nose piece is pivotally mounted so that it may be moved to keep its edge remote from the pivot point closely spaced from the periphery of the grinding wheel as the wheel wears during grinding. A mechanical connection between the nose piece and a control device for the grinding wheel motor is provided for adjusting the speed of the latter and is dependent upon the rotational position of the nose piece so that the peripheral speed of the grinding wheel may be maintained substantially constant during grinding.

This embodiment of the invention is illustrated in the accompanying drawings in which:

FIG. 1 is a side elevational view of the grinding machine constructed in accordance with the principles of this invention with a portion thereof broken away;

FIG. 2 shows a front elevational view of the grinding machine of FIG. 1 with a portion thereof broken away; and

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FIG. 3 is a sectional view taken on the plane of line 33 of FIG. 1 illustrating the pivot assembly of the nose piece of the grinding machine of FIGS. 1 and 2.

Referring now to the drawing, it will be seen that the grinding machine essentially comprises a grinding wheel 10, which is partially enclosed by a casing, generally designated 12, comprising Side walls 14 and 16 and a portion 18 extending around the periphery of the wheel 10 and connecting the side walls 14 and 16. The casing 12 is suitably supported on a frame 19 of the grinding machine.

A nose piece, generally designated 20, disposed between side walls 14 and 16, is provided at the forward upper end of the portion 18 and comprises a part 22 which extends forwardly and upwardly of the portion 18 and forms substantially a continuation thereof and an arcuate part 24 which extends downwardly from the front end of part 22 towards the periphery of the grinding wheel 10 and terminates in an edge 26.

The nose piece 20 is rotatably mounted adjacent its rear end on a shaft 28 which passes through a bore 30 (see FIG. 3). The shaft 28 is journaled in a bushing 32 in side wall 16 and carries on its outer end a lever 34 which is disposed outwardly of side wall 16 and extends forwardly of the shaft 28 as seen in FIG. 1. The shaft 28 is provided with a flange 36 on the inside of side wall 16, which flange carries a peg 38 adapted to be received in a bore 40 in nose piece 20 to secure the nose piece to the shaft 28 for rotational movement therewith.

The free end of lever 34 is connected to an elongated rod 42 at one end thereof, the other end of said rod being connected to a bracket 44, which in turn is connected to a slideable base 46 by means of an extension member 48. Slideable base 46 is mounted for reciprocating movement in an inclined upright direction on a fixed support 50. Any suitable means may be provided for permitting relative movement between base 46 and support 50. For example, one such means may comprise a plurality of pins or studs 52 secured to base 46 adapted to be received in elongated slots 54 of support 50.

An elongated externally threaded rod 55 is rigidly secured at one end to a lug 56 extending laterally outwardly from slideable base 46, the other end being threadably received in an elongated internally threaded member 57 secured to a hand wheel 58. Hand wheel 58 has a stem 61 which bears against a surface 59 mounted on frame 19 so that turning hand wheel 58 imparts reciprocating movement to the slideable base 46 through rod 55 and member 57.

Rigidly secured to slideable base 46 is a motor 60 having an output power shaft 62 to which is rigidly secured a drive pulley 64. An endless drive belt 66 is trained about drive pulley 64 and is guided over a variable speed pulley 68 suitably mounted on one end of a drive shaft 70. The grinding wheel 10 is suitably mounted on the other end of drive shaft 70 for rotation therewith.

In use, the operator visually observes the gap or distance between edge 26 of the nose piece and the periphery of the grinding wheel. As the wheel wears and this distance increases beyond a predetermined limit, the operator turns the hand wheel 58 in the proper direction to effect downward movement of motor 60 by means of member 57, rod 55 and slideable base 46. Movement of the motor and thereby drive pulley 64 increases belt tension to move belt 66 nearer to the axis of variable speed pulley 68 to increase the speed thereof and thereby grinding wheel 10. Simultaneously, the edge 26 of nose piece 20 is pivoted radially toward the periphery of grinding wheel 10 by means of extension 48, bracket 44, rod 42, lever 34 and shaft 28. Thus, by periodically adjusting the position of the nose piece to maintain the distance between edge 26 of the nose piece and the periphery of the grinding wheel at a given distance, the speed of rotation of the grinding wheel is increased to maintain a substantially constant peripheral speed of said wheel.

The side wall 14 is divided into two parts, the forward part 72 being hingedly connected to the rear part 74 to form a door which can be opened to give access to the grinding Wheel 10. The front edges of the door 72 and side wall 16 have inwardly directed flanges 76. A U-shaped member 78 is secured to the nose piece 20 on the upper front end of the arcuate part 24 and is adapted to straddle flange 76 and the forward edge of door 72. Member 78 moves with nose piece 20 as such nose piece is adjusted downwardly to prevent opening of the door 72. Nose piece 20 can be pivoted upwardly between side wall 16 and door 72 to raise member 78 upwardly out of latching engagement with door 72 to permit the opening thereof.

After the door 72 has been opened, the nose piece 20 may be slid laterally on the shaft 28 to disengage the peg 38 from the bore 40 whereafter the nose piece may be swung backwardly about the shaft 28 to give free access to the grinding wheel 10 from above.

I claim:

1. A grinding machine comprising: means for mounting a grinding wheel for rotary movement; a casing partially enclosing said grinding wheel having a portion extending around the periphery of said wheel and mounted for rotary movement on a rotatable shaft, said portion terminating in an edge disposed adjacent the periphery of said grinding wheel; and means connecting said portion and said drive means for adjusting the distance between said edge of said portion and said periphery of said grinding wheel and simultaneously adjusting the speed of rotation of said grinding wheel to maintain the peripheral speed of said grinding wheel substantially constant, said rotatable shaft being provided with a flange, and said flange having means selectively connected to said portion of said casing.

2. A grinding machine as defined in claim 1 in which said last mentioned means comprises a peg engageable with a bore disposed in said portion of said casing.

3. A grinding machine as defined in claim 2 in Which said casing has a hinged forward door portion to obtain access to the grinding wheel.

4. A grinding machine as defined in claim 1 in which said connecting means includes a lever connected adjacent one end thereof to said rotatable shaft, the other end of said lever being connected to a rod adjacent one end thereof, the other end of said rod being connected to a moveable base; and means for effecting movement of said moveable base.

5. A grinding machine as defined in claim 4 in which said means for effecting movement of said moveable base comprises a hand wheel operatively connected to said moveable base by a pair of threaded members.

6. A grinding apparatus as defined in claim 4 in which said drive means includes a motor mounted on said move able base and operatively connected to said grinding Wheel by means of a variable drive pulley.

7. A grinding machine comprising: means for mounting a'grinding wheel for rotary movement; drive means for rotating said grinding wheel; a casing partially enclosing said grinding wheel having a portion extending around the periphery of said wheel and mounted for rotary movement on a rotatable shaft, said portion terminating in an edge remote from said shaft and disposed adjacent the periphery of said grinding wheel; and means connecting said portion and said drive means for adjusting the distance between said edge of said portion and said periphery of said-grinding wheel and simultaneously adjusting the speed of rotation of said grinding wheel to maintain the peripheral speed of said grinding wheel substantially constant, said casing including side walls; said rotatable shaft being journaled in one of said side 'walls and having a flange rigidly secured thereon, and said flange having a peg engageable with a bore disposed in said portion of said casing.

8. A grinding machine as defined in claim 7 in which the other of said side walls has a hinged forward door portion to obtain access to the grinding wheel.

References Cited UNITED STATES PATENTS 2,003,495 6/1935 Ritz 51134.5 2,471,561 5/1949 Fielding 51269 2,791,067 5/1957 Falls 51-72 3,157,006 11/1964 Behlen 51134.5 3,247,621 4/ 1966 Aller 51134.5

ROBERT C. RIORDON, Primary Examiner DONALD G. KELLY, Assistant Examiner US. Cl. X.R. 51-269 

